Fuel feeding system



March 12, 1963 R. W. MAYES FUEL FEEDING SYSTEM Filed March 15, 1957 54 ILL!!! I RONALD W M INVENI OR AYES ATTORNEY United States Patent 3,080,819 FUEL FEEDING SYSTEM Ronald Wayne Mayes, Alexandria, Va. (8114 Carrick Lane, Springfield, Va.) Filed Mar. 15, 1957, Ser. No. 646,310 13 Claims. (Cl. 103-10) The present invention relates to liquid feeding systems. I The. principal Object of the invention is to provide a newand improved liquid fuel system which will quickly provide a large quantity of fluid at a engine or the like.

A. second object of this invention is to provide a primary pump and an auxiliarypump which will operate continuously until disabled or closed down.

3,080,819 Patented Mar. 12, 1963 Once the pressure in line 18 has exceeded the pressure in line 16, check valve 17 will close and the discharge of auxiliary pump 15 will be diverted to line 14 to the inlet 56 of primary pump 5. The fluid discharged frompump 15 will make up a substantial amount of the fluid needed to supply primary pump 5. The balance of the supply fuel ring of a jet The present novel fuel feeding system provides a primary pump which will continuously operate at maximum capacity by reason of the novel fuelfeeding anrangement.

The invention further provides a fuel system wherein a primary pump is relieved of unnecessary Wear and tear.

An auxiliary pump is provided which can generally perform the function of the primary pump should the primary pump fail.

. The auxiliary pump will operate in series with the primary pump under normal operating conditions and there by relieve the primary pump of extra work.

The pumps in the novel fuel feeding system will initially operate in parallel for quickly supplying a large quantity of fuel to the point of consumption, i.e., a fuel ring in a jet engine. Once a predetermined pressure is reached, the pumps will automatically be switched into a series arrangement.

The novel primary pump in the novel fuel feeding system has minimum clearance between the housing and the gears to reduce noise, leakback and ineflicient operation. The novel primary pump also acts to prevent feedback should the secondary pump fail.

A novel fuel feeding arrangement is provided for obtaining maximum output of the primary pump and for permitting the use of a smaller and lighter primary pump. -Other novel features of this invention and how the obiects are obtained will appear from this specification and the accompanying drawing which forms-a part of this application, andall of these novel features are intended to be pointed out in the claims.

J In the drawings:

FIGURE 1 shows a schematic layout of the proposed fuel feeding system; i e

FIGURE 2 shows the novel means of supplying fluid from a'reservoir to a gear pump; and

, FIGURE 3 is an enlarged fragmentary view along section line 33 of FIG. 2.

Referring first to FIGURE 1, the fuel is drawn by an auxiliary pump 15 from two lines 2 and 13 and discharges the fuel to line 16. The auxiliary pump 15, upon initially starting the turbine, will discharge through check valve 17 to lines 18 and 9 to the point of consumption. Pump 5 is of a-larger capacity, and is hereafter called the primary pump. The pump 5 draws fluid from reservoir 1 through lines 2, 3 and 4 to inlet ports 53 and 54 intermediate-the gear housing 55 of the pump 15. The points of entrance 5 3 and 54 are intermediate the ordinary inlet 56 and outlet 57 and are situated along the internal fluid paths in the primary pump 5 as shown in FIGURE 2.

Fluid is discharged to line 6 and subsequently to lines 8 and 9 which lead to the point of consumption.

, The point of consumption may be a fuel ring or nozzle .in a gas turbine type of engine or any other fuel burning apparatus. i 1

" As pointed out, the primary pump 5 and auxiliary "pump 15 initially discharge fluid to line 9 by meansof a parallel circuit.

to primary pump 5, if necessary, will be drawn through lines 2, 3 and 4 from reservoir 1 to points intermediate the inlet and outlet of gear or worm type pump 5.

It is to be understood that only one of the inlet lines 53 and 54 may be used in an alternative embodiment of the present invention, although in the embodiment shown in FIG. 1, both of the inlet lines 53 and 54 are preferred so as to provide a balanced pump 5.

--Under normal operating conditions pumps 5 and 15 are operating continuously and in series as hereinbefore pointed out. I

Should primary pump 5 become disabled so as to substantially reduce the supply of fluid being discharged, pressure in lines 6, 8, 9 and 13 will, as a result, be substantially reduced thereby enabling the discharge of pump 15 to flow past check valve 17 into lines 18 and 9 to the point of consumption. Alternatively, should pump 15 become disabled, pump 5 will draw its entire supply of fluid through lines 2, 3 and 4 and discharge an adequate supply of fluid to the point of consumption by means of lines 6, -8 and 9.

A novel feature of this invention is the ability of pump 5 to operate at maximum discharge efliciency or mechanical efliciency due to the fact that substantially any void or dearth of hydraulic fluid in the spaces between the gear teeth will be made up from the supply through lines 2, 3 and 4.

Should pump 5 be disabled as hereinabove pointed out, a quantity of fluid may be lost from line 6 back past the pump 5 to lines 4, 3 and 2. This will be kept to a minimum, depending upon the viscosity of the fluid being pumped, by maintaining a minimum clearance between the gears and the gear housing 55.

It is well known in the art that for a gear type pump the clearance between the gear and gear housing is critical. The clearance is maintained at a minimum in gear pump 5 by the use of elastomeric or plastic linings 3'1, 32. 33 and 34 as shown in FIGURE 2.

Pumps 15 and 5 as shown in FIGURE 1 may operate from the same drive shaft, or preferably, be operated from ing upon the wishes of the user. In addition, pressure relief valve 20 may be inserted between the discharge line 9 and the reservoir 1. The function of a by-pass line is well known to those skilled in the art and is utilized to relieve and regulate the pressure in the discharge line 9.

' A brakemay be added to either of gear pumps 5 and 15 to prevent windmilling when it is idle or becomes disabled.

Alternatively, a one-way brake of a spring detent and ratchet type may be combined with the drive shafts of either of gear pumps 5 and 15 to permit the gears to discharge fuel in only one direction.

It is also contemplated that relief bypasses may be utilized in connection with either of the gear pumps.

It is further contemplated that there may be more than two pumps in that, if desired, a multiplicity of pumps which may pump either in series, as disclosed herein, or in series in a stepped pressure system may be utilized.

The fluid is directed from the reservoir 1 to pump 5 through lines 3 and 4 to the base or root of the'gear teeth as shown in FIGURE 3. Alternatively, the fluid may be directed to other points presenting minimum resistance to the incoming fluid. This resulting advantage is obvious in that the fluid pumping efliciency of the primary pump is substantially increased and noise is reduced. In addition a smaller capacity primary pump may be used which will result in a saving of weight.

I claim:

1. A liquid feeding system comprising, discharge conduit means, first gear pump means having toothed gears and a housing with a plurality of liquid inlets and a liquid outlet formed therein, a first one of said liquid inlets be ing generally oppositely disposed relative to said liquid outlet of said first gear pump means so as to permit the liquid to be supplied to said first gear pump means in a conventional manner, asecond one of said plurality of liquid inlets being formed in the housing of said first gear pump means in such a manner as to open into and fill any voids at the base circle of at least one of said toothed gears between said generally oppositely disposed liquid inlet and said liquid outlet, first conduit means connecting said first gear pump means to said discharge conduit means, second gear pump means with a housing having conventional generally oppositely disposed liquid inlet and outlet formed therein, second conduit means connecting said outlet of said second gear pump means to said discharge conduit means, check valve means'disposed in said second conduit means to prevent reverse liquid flow through said second conduit means back into said second gear pump means, and third conduit means having one end connected into said second conduit means between said check valve means and said second gear pump means and having the other end connected to at least one of said plurality of liquid inlets of said first gear pump means, said first gearpump means having minimum clearance between said toothed gears and said housing, and said first and second gear pump means pumping liquid in parallel until fluid pressure in said discharge conduit means is sufficie'nt to cause said check valve means to close whereupon substantially all liquid discharged by said second gear pump means is fed in series to said first gear pump means.

2. A liquid feeding system as set forth in claim 1, wherein said first gear pump means has a capacity to discharge a greater quantity of liquid than said second gear pump means.

3. A liquid feeding system as set forth in claim 1, wherein said housing of said first gear pump means has an internal lining of a flexible nonmetallic material disp'o's'ed between said housing and said toothed gears for maintaining a minimum clearance therebetween.

4. A liquid feeding system as set forth in claim 1, further comprising fourth liquid conduit means connected at one end to one of said plurality of inlets of said first gear pump means and adapted to be connected at the other end thereof to a liquid reservoir.

5. In a liquid fuel feeding system, a first meshing gear pump of small volumetric capacity, a second meshing gear pump of large volumetric capacity, a first supply line series connecting a discharge side of said first meshing gear pump to an intake side of said second meshing gear pump, the intake side of said first meshing gear pump to a liquid fuel supply, a third supply line adapted to connect the intake side of said second meshing gear pump to the liquid fuel supply, said third supply line being connected to and opening into voids at the base circle of at least one of the gears of said second meshing gear pump between said intake side and said discharge side thereof, a bifurcated discharge line having a first branch line connected to the discharge side of said first meshing gear pump and a second branch line connected to the discharge side of said second meshing gear pump, and one-way check valve means in said first branch line adapted to check reverse flow in said first branch line back into said first meshing gear pump when said valve means is closed and adapted to permit parallel operation of said pumps when said valve means is open.

6. In a liquid fuel feeding system as set forth in claim 5, wherein said second meshing gear pump has elastomeric means for maintaining minimum clearance between the housing and the gears.

7. In a liquid fuel feeding system as set forth in claim 5, wherein said second meshing gear pump comprises meshing gear means and a housing having substantially zero clearance therebetween for preventing any substantial leakage of fluid therethrough so that should said second meshing gear pump be stopped, substantially no liquid fuel will be lost back to said source of liquid fuel supply.

8. In a liquid feeding system comprising, in combination, a primary pump having a housing with meshing gear means journaled therein, a secondary pump, said housing of said primary pump having two liquid inlets and a liquid outlet formed therein, said secondary pump having a housing with a liquid inlet and a liquid outlet formed therein, supply lines connected to at least one of said inlets of each of said pumps for conducting a supply of liquid to each of said pumps, a feed line connecting said outlet of said secondary pump to the other of said inlets of said primary pump in noncommunicating relationship with said supply lines and for connecting said pumps in series, a discharge line connected to each of said outlets of said pumps so that said pumps can be operated in parallel, said discharge lines feeding to a common discharge line, and a check valve in said discharge line of said secondary pump disposed in such a manner that the check valve will close and the pumps will operate in series when the pressure in the common discharge line is greater than in said feed line connecting said two pumps, the improvement comprising, said housing for said primary pump having at least one of said inlets formed therein in such a manner as to only open into voids at the base circle of the gear teeth of at least one of said primary'pump gear means along a path of liquid flow caused by the impelling action of the gear teeth.

9. In a liquid feeding system as set forth in claim 8; the improvement further comprising, flexible nonmetallic means lining the inside portions of said housing, and said lining being in juxtaposition with the teeth of said gear means for maintaining a substantially zero clearance between the teeth of said gear means and the inside of said housing and thereby isolating liquid between the gear teeth along the path of liquid flow.

10. In a liquid feedingsystem as set forth in claim 9, wherein said housing comprisesa pair of opposed and substantially parallel walls each having the inside portions thereof which are in' juxtaposition with the teeth of said gears lined with said nonmetallic means.

11. In a liquid feeding system as set forth in claim 9, said housing comprises peripheral wall means andside walls, said side walls are connected together by said peripheral wall means, and the inside of said peripheral wall means and said side walls are completely lined with said nonmetallic means for maintaining a substantially zero clearance between the peripheries of said gear means and said peripheral wall means.

12. In a gear pump for pumping liquids, a housing having opposed side walls and a peripheral wall connecting said opposed side walls together, meshing gear means journaled in said opposed side walls, liquid inlet means and liquid outlet means in said housing in opposite sides thereof and arranged in such a manner that liquid can be supplied to said gear pump, impelled by the teeth of said gears around the peripheries thereof and discharged out the other side of said gear pump, and additional liquid inlet means locatedradially inwardly from a liquid flow path in the gear pump in such a manner relative to said gear teeth as to open only into voids at the roots of said gear. teeth, and said additional liquid inlet means being in at least one of said opposed side walls intermediate said inlet means and said outlet means in said housing.

13. In a gear pump as set forth in claim 12, further comprising flexible nonmetallic means at least partially lining the inside walls of said housing for restricting any 5 low pressure side thereof.

References Cited in the file of this patent UNITED-STATES PATENTS Vogt Mar. 21, 1933 Aldrich Nov. 10, 1942 Crosby Jan. 2, 1945 Heckert July 29, 1947 Thacher May 31, 1949 Ray Dec. 5, 1950 Eames June 10, 1952 Digney Sept. 23, 1952 Maisch Nov. 25, 1952 Mahlon Mar. 10, 1953 Banker Apr. 24, 1956 Gaubatz Sept. 4, 1956 Compton Jan. 21 1958 

1. A LIQUID FEEDING SYSTEM COMPRISING, DISCHARGE CONDUIT MEANS, FIRST GEAR PUMP MEANS HAVING TOOTHED GEARS AND A HOUSING WITH A PLURALITY OF LIQUID INLETS AND A LIQUID OUTLET FORMED THEREIN, A FIRST ONE OF SAID LIQUID INLETS BEING GENERALLY OPPOSITELY DISPOSED RELATIVE TO SAID LIQUID OUTLET OF SAID FIRST GEAR PUMP MEANS SO AS TO PERMIT THE LIQUID TO BE SUPPLIED TO SAID FIRST GEAR PUMP MEANS IN A CONVENTIONAL MANNER, A SECOND ONE OF SAID PLURALITY OF LIQUID INLETS BEING FORMED IN THE HOUSING OF SAID FIRST GEAR PUMP MEANS IN SUCH A MANNER AS TO OPEN INTO AND FILL ANY VOIDS AT THE BASE CIRCLE OF AT LEAST ONE OF SAID TOOTHED GEARS BETWEEN SAID GENERALLY OPPOSITELY DISPOSED LIQUID INLET AND SAID LIQUID OUTLET, FIRST CONDUIT MEANS CONNECTING SAID FIRST GEAR PUMP MEANS TO SAID DISCHARGE CONDUIT MEANS, SECOND GEAR PUMP MEANS WITH A HOUSING HAVING CONVENTIONAL GENERALLY OPPOSITELY DISPOSED LIQUID INLET AND OUTLET FORMED THEREIN, SECOND CONDUIT MEANS CONNECTING SAID OUTLET OF SAID SECOND GEAR PUMP MEANS TO SAID DISCHARGE CONDUIT MEANS, CHECK VALVE MEANS DISPOSED IN SAID SECOND CONDUIT MEANS TO PREVENT REVERSE LIQUID FLOW THROUGH SAID SECOND CONDUIT MEANS BACK INTO SAID SECOND GEAR PUMP MEANS, AND THIRD CONDUIT MEANS HAVING ONE END CONNECTED INTO SAID SECOND CONDUIT MEANS BETWEEN SAID CHECK VALVE MEANS AND SAID SECOND GEAR PUMP MEANS AND HAVING THE OTHER END CONNECTED TO AT LEAST ONE OF SAID PLURALITY OF LIQUID INLETS OF SAID FIRST GEAR PUMP MEANS, SAID FIRST GEAR PUMP MEANS HAVING MINIMUM CLEARANCE BETWEEN SAID TOOTHED GEARS AND SAID HOUSING AND SAID FIRST AND SECOND GEAR PUMP MEANS PUMPING LIQUID IN PARALLEL UNTIL FLUID PRESSURE IN SAID DISCHARGE CONDUIT MEANS IS SUFFICIENT TO CAUSE SAID CHECK VALVE MEANS TO CLOSE WHEREUPON SUBSTANTIALLY ALL LIQUID DISCHARGED BY SAID SECOND GEAR PUMP MEANS IS FED IN SERIES TO SAID FIRST GEAR PUMP MEANS. 